Technical Field
The present invention relates to a recording apparatus represented by facsimile machines, printers, and the like.
Related Art
A so-called serial printer is a printer that completes the recording by alternately executing a paper transport operation of a predetermined amount of paper and a recording operation that accompanies the movement in the direction of the paper width of a carriage provided with a recording head. In addition, the types of inkjet printers are a type that provides an ink cartridge in the carriage and a type that provides the ink cartridge independent of the carriage and connects the ink cartridge to the carriage by an ink tube. In either type of serial printer, recording is performed by the reciprocating operation of the carriage in a predetermined range.
In an inkjet printer, a pair of transport rollers for transporting a recording sheet, as an example of a medium, is provided on the upstream side of the recording head. The transport roller pair is usually configured from a drive roller that is driven by a motor and a driven roller that presses toward the drive roller (e.g., Japanese Laid-Open Patent Publication No. 2006-247932).
The drive roller is produced by forming a high friction layer on the outer peripheral surface of a solid metal shaft or a hollow metal shaft. The driven roller is formed by resin molding. The recording paper is transported to the downstream side by the rotational drive of the drive roller in the state in which the paper is pinched by the drive roller and the driven roller.
Here, when the recording paper is transported by this kind of transport roller pair, the back edge of the paper is forcefully ejected when the transport roller pair releases. As a result, the phenomenon of disruption of the transport accuracy and the so-called kicking phenomenon occur. This kind of kicking phenomenon conspicuously occurs particularly with thick recording paper (e.g., glossy paper, paper board).
In addition, there is a demand for a further reduction in printer size. In particular, users are requesting further reductions in the sizes of mobile printers that they expect to carry.
Now, when the width dimension of the printer is examined, the width dimension is determined for the most part by the width of the movement region of the carriage, and the sizes and the placement positions of structural elements that are arranged on the outside of the movement region. Because the movement region of the carriage is determined by the paper width and cannot be reduced, a reduction of the space occupied by structural elements that are arranged outside of the carriage movement region is essential in reducing the width dimension.
Japanese Laid-Open Patent Publication No. 2006-289770 discloses a configuration in which an encoder scale is arranged outside of the carriage movement region as an example.
As a means to suppress the kicking phenomenon described above, Japanese Laid-Open Patent Publication No. 2006-247932 discloses a technology that forms in advance a gap smaller than the thickness of the recording paper between the drive roller and the driven roller. According to this, the kicking phenomenon can be suppressed even if the thickness of the recording paper is increased.
However, in the structure described above in Japanese Laid-Open Patent Publication No. 2006-247932, sometimes it was difficult to adequately manage the gap between the drive roller and the driven roller, and an adequate pinching force was not obtained when the thickness of the recording paper was thin. In these cases, the problem was that the kicking phenomenon occurred. That is, the problem was the difficulty in more satisfactorily (reliably) suppressing the kicking phenomenon in a simple structure.
Also, a reduction in the height dimension, in addition to the width dimension, of the apparatus is also requested for printers. However, when the height dimension of the apparatus is reduced, the volume of the carriage becomes smaller. In particular, a smaller ink cartridge must be designed for the type that provides the ink cartridge in the carriage. Therefore, if the carriage volume is ensured while the height dimension of the apparatus is reduced, the width of the carriage must be increased, but the width dimension of the apparatus will increase. In other words, there is a trade-off relationship between the carriage volume, namely the volume of the ink cartridge, and the width dimension of the apparatus. The problem was the difficulty in establishing both.